Thyroid tuberculosis associated with papillary microcarcinoma: case report and review of literature

Thyroid tuberculosis (TB) is extremely rare. Infection may first occur in the thyroid gland or may be secondary to TB in other parts of the body. The diagnosis is rarely made clinically because the disease's variable presentation often resembles that of a malignancy or an euthyroid nodular goiter.

We present the case of a 40-year-old woman, who presented multiple thyroid nodules in both lobes. Two of these nodules were classified as EU-TIRADS V (European Thyroid Imaging and Reporting Data System). The ultrasound also found an adenopathy of the inferior part of the jugular lymphatic chain, in favor of malignancy. The histopathological examination after total thyroidectomy showed thyroid TB, associated to a papillary microcarcinoma of the right thyroid lobe, and the final examination of the adenopathy showed similar granulomas with caseous necrosis, and no signs of metastasis.

Thyroid TB is very rare. Its diagnosis is difficult due to a lack of specific signs and symptoms, which is why the diagnosis is most commonly made on pathological examination after thyroid surgery. It is well known that mycobacterial infection creates an environment of chronic and persistent inflammation, with possible DNA damage. This can create a microenvironment that is highly conductive to carcinogenesis, which could explain the discovery of papillary microcarcinoma in addition to thyroid TB in our patient.

This report presents a rare case of malicious growth development of thyroid nodules and thyroid TB. Therefore, physicians must always be vigilant when managing thyroid nodules, as there is always the possibility of malignant lesions associated to an inflammatory or infectious cause.